Fermentation
Lactic Acid Bacteria are used in the fermentation of many food items from yogurt to pickles. Here is a more exact list of the fermented food item and the region that it is found in:
- Western world: yogurt, sourdough breads, sauerkraut, cucumber pickles and olives
- Middle East: pickled vegetables
- Korea: kimchi (fermented mixture of Chinese cabbage, radishes, red pepper, garlic and ginger)
- Russia: kefir
- Egypt: laban rayab and laban zeer (fermented milks), kishk (fermented cereal and milk mixture)
- Nigeria: gari (fermented cassava)
- South Africa : magou (fermented maize porridge)
- Thailand : nham (fermented fresh pork)
- Philippines : balao balao (fermented rice and shrimp mixture
This shows that the Lactic Acid Bacteria are popular all around the world.
Process
Lactic Acid Bacteria, like those of the Leuconostoc genus, are used at the begining of the fermentation process. Leuconostoc mesenteroides are added to the item that needs to be fermented, lets say cabbage. Then the bacterium begins to produce acids and raise the acidity level of the cabbage to .25%-.3%. Then the bacteria start to slow down and die off. L. mesenteroides is then replaced by lactobacilli, another acid creating bacterium. That raises the acidity level to 1.5%-2.0%. Then lactobacilli dies off and is replaced by L. pentoaceticus(another Lactic Acid Bacteria)which finishes the process by raising the acidity to 2% or 2.5%.
L. mesenteroides produces carbon dioxide along with the acid. The acids rapidly lower the ph which inhibits the developement of undesirable micro-organisms. The carbon dioxide that it produces takes place of the oxygen in the area which makes the area anaerobic and suitable for the growth of the lactobacilli which carry on the fermentation process after the L. mesenteroides dies off. The removal of oxygen also helps to preserve the color of vegetables.
L. mesenteroides also ferments lactose, which is found on the food that needs to be fermented, into lactic acid. This acid is responsible sour taste and it improves microbiological stability so that the fermented food can laste longer. Especially in sauerkraut, the sugars in cabbage are converted to lactic acid and serves as a presevative.
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